Federal prosecutors are probing the finances of the powerful correction-offic­ers union, the Post has learned.

The Manhattan US Attorney’s Office has subpoenaed financial documents from the treasurer of the 9,000-member Correction Officers Benevolent Association, said union President Norman Seabrook.

“I will cooperate with the US attorney’s investigation. I have nothing to hide,” said Seabrook, adding that he has not been personally interviewed or subpoenaed.

The investigation appears to focus on allegations made in a lawsuit filed by union secretary William Valentin, a 22-year of the Department of Correction veteran, who

asked a court in January to oust Seabrook for allegedly being a paranoid, ­vindictive bully.

Valentin said in court papers that the union treasurer told him in a members-only cigar lounge that Seabrook sank $5 million in COBA funds — without union-board approval — into a company or hedge fund that twice paid for Seabrook’s travel to Israel.

Seabrook and the union treasurer said in sworn affidavits there was nothing fishy about the investment.